During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.
August 27th 2011
We have an exciting week behind us. And that's putting it mildly.
In the last SIE update I referred several times to the unfulfilled potential the ice pack is showing this melting season, even making it the title of the update. A coupe of days later we saw some of that potential being put to use when a big cyclone ripped through the Beaufort and Chukchi regions, causing an unprecedented (I think) case of flash melting in a huge area of the ice pack. Normally you get a bit of ice melt/compaction everywhere at the edges of the ice pack, but this week we saw a massive amount of ice just disappearing from the radar one day to the next. Stunning stuff.
Of course, it is impossible for so much ice to disappear in just 24 hours, but the cyclone managed to disperse the floes, which probably got washed by water in the process, in such a way that concentration fell below the 15% threshold combined with some other factors (there has been much speculation regarding this matter in the Flash melting post). Some of the ice could show up again in the coming days if the winds push it together.
The cyclone was as short-lived as it was big, which means there still is a lot of untapped potential out there. The satellite images and sea ice concentration maps don't lie and show us how weak the ice is at the edges. We even see the water that has been warmed up to the brim in the Laptev Sea starting to eat its way into the ice pack, towards the North Pole.
As usual, weather patterns in these last 2-4 weeks of the melting season will determine the final outcome. But what makes this year so interesting is that this dominant influence is being superseded by the state of the ice. In other words, the ice determines how much influence weather patterns are allowed to have. This week's cyclone, for instance, would have actually made sea ice extent jump up only ten years ago because of its diverging power. But you can't diverge what you disintegrate.
Barring some really strong weather patterns that keep the ice in place and freeze the water over at the edges, we are in for a final phase of the melting season where everything is possible.
Sea ice extent (SIE)
Here's the current IJIS SIE graph:
IJIS extent is about to break through the 5 million square km barrier, for the fourth time in the satellite record, after 2007, 2008 and 2010. This year has managed to nibble off some more of 2007's lead (with the help of a very late century break due to the 'flash melting'), but a difference of 191K square km is still quite significant at this stage of the melting season. 2007 is having some very slow days at the end of the week, so maybe 2011 can get closer still. In the meantime, it seems to be fending off 2008's massive attack quite well, still leading by almost 300K square km.
The current difference between 2011 and the other years is as follows:
- 2005: -820K (-45,000)
- 2006: -984K (-37,697)
- 2007: +191K (-57,041)
- 2008: -295K (-70,333)
- 2009: -582K (-48,654)
- 2010: -468K (-51,736)
Between brackets is the average daily extent decrease for the month of August. 2011's average daily extent decrease for August is currently -59,633 square kilometers.
If 2011 loses as much sea ice extent as...
- 2005 did after this date it will bottom out at 4.50 million square km
- 2006 did after this date it will bottom out at 4.80 million square km
- 2007 did after this date it will bottom out at 4.45 million square km
- 2008 did after this date it will bottom out at 4.41 million square km
- 2009 did after this date it will bottom out at 4.67 million square km
- 2010 did after this date it will bottom out at 4.35 million square km
Sea ice area (SIA)
As I wrote in yesterday's blog post on sea ice area, 2011 guaranteed itself a second place on all area graphs. It even took over first spot from 2007 in the Cryosphere Today sea ice area data file today and is just 65K shy of the record minimum sea ice area. But as SIA tends to go up and down arbitrarily, and with big jumps too, it's difficult to tell if the record will be broken or not. Nevertheless, I know what I would bet on.
The Cryosphere Today SIA anomaly graph is of course showing the largest anomaly ever recorded for this date:
As we can see on the Regional Graphs page, the Arctic Basin and Canadian Archipelago keep going down some more (and are lowest on the MASIE charts). There still is some slush puppie ice left in the East Siberian Sea that will probably completely melt out, and in the Greenland Sea SIA and SIE have been going down some more.
Cryosphere Today area per IJIS extent (CAPIE)
One of the reasons I say there is still quite a bit of untapped potential in the Arctic ice pack, is the fact that CAPIE is still very low. This means that the ice pack is diverged and under the right circumstances could be compacted a lot, which is what happened in 2007. As we see on the graph CAPIE shot up real fast around this time in 2007:
Sea Level Pressure (SLP)
Let's cut straight away to the animation of SLP images from the DMI Centre for Ocean and Ice of the past week:
We see the big, blue cyclone forming over Alaska, doing some shredding and dispersing over the Beaufort and Chukchi regions and then quickly dissipate. There currently is a distribution of sea level pressure areas that has tentatively kicked off ice transport towards the Atlantic (again), but it takes a couple of days to create a constant rhythm and it's highly unsure if things will remain stable enough for it to remain so.
Because this is what the weather has in store for the Arctic the coming five days, according to the ECMWF weather forecast maps:
I don't see anything there that makes me believe there will be a significant extent and area decrease. At least not due to compaction and transport.
There still is a lot of weak ice. No extreme weather is needed to push it over the edge, just average weather will do. If we do get something like a strong Arctic Dipole and a clockwise spinning Beaufort Gyre, the potential is such that 2011 could break all records on all graphs and all datasets in the coming two weeks. But as always, a fast onset of freezing temperatures and winds blowing the ice towards the coasts could still nip record tentatives in the bud.
It's not really clear what will happen the coming week. We will have to take it day by day. Another serious cyclone would be fun though.
2-4 weeks left to go...
TIPS - Other blog posts and news articles concerning the Arctic and its ice:
NOAA ClimateWatch Magazine: Summer Heat Unravels Arctic’s Icy Blanket